Because covid19 exitement in germany are respiratory protections sold out very often now. This is the a quick and easy plan-b and probably better than nothings.
It is a simple holder to keep filter fleece around mouth and nose (e.g. kitchen roll as placebo or better electret-filter fleece from a vaccum cleaner bags). No serious protection is guaranteed. Someone should add a valve or adjust the geometry to more general face shapes. Using PLA is working for me, but not very well. Please, try to use something more flexible material and post your experiences.
Probably a lot of possible strings will work, in my case silicon-rubber-tubes did the job: - outer diameter: 5mm - inner diameter: 3mm - wall size (thickness): 1mm
If you dont have silicon or will not printing clamps but have some neodym magnets available it is possible to hold the fleece with it too.
Update 14.03.2020: - adding clamps left and right to hold the fleece in position - adding conic silicon tube terminators to connect clamps and bind it losely to the frame - breaking a PLA-print at beginning the infills seems to give a flexible but stable enough frame thank you 'rybaiho' for your comment, will adapt the cad files next
Update 29.03.2020: did some investigations with a disco-fog-machine and found out that "kitchen-roll" is NOT a good filter fleece! To protect you from the critical droplet infection (diameter ca 2µm) it is important to use electret filter material (e.g. fine dust filter of a vaccuum cleaner bags). look amazon e.g.: - Elektret-Filtertüte Sebo-Filterbox D 8120 ( https://amzn.to/2JhEnsh ) - Sebo 5093ER Filterbox ( https://amzn.to/3dnqTcg ) - Please also take a look to the MASK designed by IridiumMan: ( https://www.thingiverse.com/thing:4247260 ) for my oppinion they did the job perfectly!